Billingen (Lower Arenig/Lower Ordovician) sediments of the St. Petersburg region, northwest Russia and the Leba area, northern Poland of the East European Craton yield acritarch assemblages, which are largely homogenous though displaying minor compositional differences that probably reflect a gradient from inner to outer shelf environments. Comparison with coeval acritarch microflora from the Yangtze Platform, South China, shows an overall similarity between Baltoscandian and South Chinese phytoplankton. The widespread uniformity in the fossil microphytoplankton may be related to the extensive global ‘evae’ sea-level transgression, which characterized the Billingen time. This suggests that during the Tremadoc through early Arenig times, acritarch assemblages displayed essentially an undifferentiated cold-water and oceanic character along the whole margin of Perigondwana in the South, as well as on the South Chinese and Baltic platforms, at middle latitudes (Mediterranean oceanic Realm). Despite this overall similarity, however, some typical taxa of the high-latitude Mediterranean Province (Arbusculidium, Coryphidium and Striatotheca) occur in South China, but are absent in Baltica. This discrepancy is explained as caused by differences in climatic and physiographic conditions that prevailed at the two palaeocontinents at this time. The inferred pattern of oceanic circulation during the Lower Ordovician is consistent with the palynological evidence of a prevailing warmer climate in Baltica than in South China, although the two palaeocontinents occupied the same palaeolatitudinal position.
The Ordovician from boreholes Dobre 1 and Sokolow Podlaski 1 (western part of the Podlasie depression) The Ordovician stratigraphy from two new boreholes has been worked out and the equivalents have been established of the uppermost Tremadocian, the Arenigian, and the Lower Llanvirnian. The lithology of the Ordovician from these profiles resembles that of contemporaneous deposits from Scandinavia. The conodont fauna contains elements known both from the Scandinavian and the Peribaltic regions. The graptolites and brachiopods indicate direct communication routes with the Holy Cross Mts. area and with northern Europe. In the Podlasie depression, the Ordovician transgression occurred gradually from E to W; the transgressive deposits were associated with the glauconite facias.
STRATlGRAPHY OF THE PALEOZOlC SEDIMENTS FROM BOBEHOLE STROŻYSKA 5 (MIECHOW TROUGH, S POLAND) The stratigraphy is given of the Paleozoic sediments from borehole Strozyska 5 (eastern part of the Miechow trough). Certain stratigraphic members of the Ordovician, Silurian, Devonian and Carboniferous are faunistically documented.
Bezzawiasowe brachipody z donego ordowiku polnocnej Polski
Some inarticulate brachiopods, including 6 new species and 1 new genus, are described from lowermost Ordovician limestone from vicinity of Łeba, northern Poland. The assemblage is dominated by acrotretids some of which are closely related to some Scandinavian species. The described taxa may be of value in correlating upper Tremadocian and lower Arenigian deposits.
Stratygrafia i nowe dane o tektonice utworow ordowiku w kamieniolomie w Miedzygorzu (wschodnia cześc Gor Świetokrzyskich)
The Ordovician strata cropping-out at Miedzygorz represent the Miedzygorz Sandstones Formation and the Mojcza Limestones Formation (sensu Bednarczyk 1981). The Miedzygorz Sandstone Formation is correlated with the upper Tremadocian (the Kleczanow Sandstone Member), Upper Arenigian (the Chelm Conglomerate Member) and Lower Llanvirnian (the Dyminy Orthid Sandstone Member). The Mojcza Limestone Formation (the Mokradle Dolomite Member) corresponds to the lower Caradocian. Earlier observations about strong reduction of all Ordovician chronostratigraphic units are corroborated. In the quarry, the Kleczanow Sandstone Member and the Dyminy Orthid Sandstone Member make small tectonic unit consisting of 5 or more scales thrusted over each other in result of pressure of the Cambrian rocks from the north (the Łysogory unit) onto the Ordovician-Silurian sequence making the core of the Miedzygorz Syncline. The Mokradle Dolomite Member is a fragment of the northern limb of the Miedzygorz Syncline. The rocks are thrown southward and partly squized out due to action of the Lower Ordovician tectonic scales thrown from the north. East of the Miedzygorz quarry the Ordovician rocks were completely squeezed out. The recent research allows to presume that the Ordovician strata at Miedzygorz form a separate tectonic unit which owes its origin to the same tectonic action which has formed the Holy Cross Dislocation.
Utwory ordowiku odslaniające sie w kamieniolomie w Miedzygorzu reprezentują dwie jednostki litostratygraficzne: formacje piaskowcow z Miedzygorza i formacje wapieni z Mojczy. Formacja piaskowcow z Miedzygorza jest korelowana z gornym tremadokiem (ogniwo piaskowca z Kleczanowa), gornym arenigiem (ogniwo zlepienca z Chelma) i z dolnym lanwirnem (ogniwo piaskowca orthidowego z Dymin). Formacja wapieni z Mojczy jest tu reprezentowana przez ogniwo dolomitu z Mokradla i odpowiada dolnemu karadokowi. W wyniku badan potwierdzono wcześniejsze obserwacje o silnej redukcji tektonicznej poszczegolnych jednostek chronostratygraficznych. W polnocno-wschodniej cześci kamieniolomu ogniwo piaskowca z Kleczanowa i ogniwo piaskowca orthidowego z Dymin tworzą malą jednostke tektoniczną zlozoną z conajmniej 5 lusek, nasunietych jedna na drugą na skutek nacisku skal kambryjskich z polnocy na skaly ordowiku. W poludniowo-zachodniej cześci kamieniolomu odslaniają sie skaly ogniwa dolomitu z Mokradla stanowiące fragment polnocnego skrzydla synkliny miedzygorskiej. Skaly środkowego ordowiku są odwrocone na poludnie i cześciowo wyciśniete na skutek nasuniecia z polnocy dolnoordowickich lusek. Na wschod od kamieniolomu skaly ordowiku zostaly calkowicie wyciśniete. Obecne badania pozwolily wyciągnąc wniosek, ze dolny ordowik w Miedzygorzu reprezentuje oddzielną jednostke tektoniczną utworzoną w wyniku tego samego waryscyjskiego procesu tektonicznego, ktory spowodowal powstanie dyslokacji świetokrzyskiej.
The sedimentary cover of the East European Platform in the Łeba area (north-western Poland) encloses a Cambrian sequence that comprises almost all the equivalents of the stages distinguished in the classical section of Scandinavia. On the basis of macrofossils and partly microfossils the following zones and subzones have been recognized: MobergelIa, Hollmia, Protolenus (Lower Cambrian), Eccaparadoxides oelandicus (E. insularis, E. pinus), Paradoxides paradoxissimus (Hypagnostus parvifrons), Paradoxides forchhammeri (Middle Cambrian), Homagnostus obesus and Agnostus pisiformis, Orusia lenticularis, Peltura minor, and Peltura scarabeoides (Upper Cambrian). The Cambrian sediments overlie here the terrigenic sediment (Smoldzino Formation) of Vendian age.
Within the strongly tectonically disturbed region of Koszalin-Chojnice, fragments of Ordovician sediments have been found in 12 boreholes drilled by the Oil Research Survey and in two other ones drilled by the Geological Institute. On the presence of graptolites these sediments, developed in a silty facies, have been referred to the Llandellian and Caradocian including the Dicranograptus clingani Zone. In the SE part of tile above region the occurrence has been noted of tuffite layers.
